Researchers warn prosthetic valve increases risk of death

A new research found that patients who undergo a transcatheter aortic valve replacement (TAVR) suffer an increased risk of death and heart failure.

Researchers from the University of Pennsylvania stated that the implanted heart valve is too small for the patient which can lead to inadequate blood flow. The team also found that the risk of death and heart failure readmissions was 19 per cent and 12 per cent higher, respectively, after one year, as compared to patients without severe PPM.

"This is an important contemporary snapshot of what's happening in the real world with commercial TAVR procedures," said the study's lead author Howard C. Herrmann. "This is the first study that is large enough to demonstrate meaningful data associated with PPM for a relatively new procedure like TAVR. Based on these findings, prosthesis-patient mismatch (PPM) is an important problem in this population, one that deserves greater awareness among operators. And being aware of it is the first step in trying to prevent it."

TAVR was approved by the Food and Drug Administration in 2011 for the treatment of aortic stenosis, a narrowing of the heart's aortic valve, and has revolutionised valve replacement options for patients with this disease who are too sick or too high risk for surgical (open-heart) valve replacement (SAVR). This minimally invasive, catheter-based approach allows physicians to replace the aortic valve without a need to remove the old, damaged one.

Of the 62,125 patients who received TAVRs in the United States between 2014 and 2017 and who were evaluated, researchers found 12 per cent experienced severe PPM, while 25 per cent had moderate PPM. Researchers collected and analysed patient data to further study outcomes. After 30 days, patients with severe PPM had higher rates of heart failure hospitalisation, stroke, and death.

Historically, PPM has been associated with worse outcomes after SAVR, however, less has been known about the incidence, outcomes, and predictors of PPM in TAVR patients. Past studies have been small, with limited follow up, and some from single centers--combined, they only represent 4,000 patients--and measurement techniques for the valve opening have been inconsistent.

PPM is a mismatch of the blood flow dynamics of the prosthetic valve and the amount of blood the heart needs to pump to the rest of the patient's body. For example, having too small of a valve in a person with a large body surface area (height and weight) affects their ability to get enough blood flow when they exercise.

In previous studies, severe PPM in both SAVR and TAVR patients have been associated with higher risk of death and hospital readmission, decreased exercise abilities, and a higher rate of valve deterioration over time. The authors identified several predictors of PPM, including patients with smaller valve prosthesis, those who had a larger body surface area or patients who are female or younger.

The findings appeared in the Journal of the American College of Cardiology.